Certain devices such as television signal receivers may be capable of receiving and processing analog and/or digital broadcast signals. With such devices, a user-initiated channel setup process may be performed in order to determine the analog and/or digital broadcast channels available in a given area. Such a channel setup process may for example require a search for both analog broadcast channels, such as National Television Standards Committee (NTSC) channels, and digital broadcast channels, such as Advanced Television Standards Committee (ATSC) channels.
According to one conventional channel setup process, a frequency channel is tuned, and a digital channel acquisition operation is performed. If the digital channel acquisition operation is successful (i.e., a valid digital broadcast channel is detected on the tuned frequency channel), then the digital broadcast channel is added to a list of valid broadcast channels. Alternatively, if the digital channel acquisition operation is unsuccessful (i.e., a valid digital broadcast channel is not detected on the tuned frequency channel), then the digital channel acquisition operation is terminated, and an analog channel acquisition operation is performed. If the analog channel acquisition operation is successful (i.e., a valid analog broadcast channel is detected on the tuned frequency channel), then the analog broadcast channel is added to the list of valid broadcast channels. Alternatively, if the analog channel acquisition operation is unsuccessful (i.e., a valid analog broadcast channel is not detected on the tuned frequency channel), then the analog channel acquisition operation is terminated, and another frequency channel is tuned where the digital and analog channel acquisition operations are repeated.
With the aforementioned channel setup process, the longest amount of time in searching a particular frequency channel occurs when no signal is present on that frequency channel since both the digital and analog channel acquisition operations must be performed in order to gain confidence that there is really no signal present. In such cases, the overall time required for the channel setup process may become unduly protracted, and therefore unacceptable to many users.
Accordingly, there is a need for a technique for performing channel detection in devices such as a television signal receiver which avoids the foregoing problems, and is capable of quickly determining the analog and/or digital broadcast channels available in a given area. The present invention addresses these and other issues.